Re: uniqueness of cluster ellipticals

From: Marc Postman (postman@stsci.edu)
Date: Tue Jan 24 2006 - 17:17:34 PST

  • Next message: Kyle Dawson: "(no subject)"

     From our (Lori + me) work with Bev Oke, the <SFR> for spectral class
    type "k" (strong 4000 A break + strong Ca HK) galaxies in clusters at
    z=0.9 is about half as high as it is for spectral class type "k"
    galaxies not in the clusters (0.89 vs 1.67 solar masses/year). There
    are fewer such k-type field galaxies of course but the cluster k-types
    seem to be producing stars at a lesser rate. However, the significance
    of this difference is marginal given the small number of galaxies in
    this bin. Lori's new survey should do a far better job at quantifying
    this. Still, this may be another mild indication that clusters are
    better places to find dust-free early types. Note that k-type
    correlates fairly well with morphology but it is a broad range,
    encompassing S0 and E (and possibly some Sa).

    Marc

    On Jan 24, 2006, at 7:42 PM, Lori Lubin wrote:

    >
    > We have not quantified it entirely, but based on the first look, we
    > also
    > see a higher fraction in the field.
    >
    > Cheers,
    > Lori
    >
    >
    >
    ------------------------------------------------------------------------
    -------------------
    Marc Postman Email: postman@stsci.edu
    STScI - CMO Phone: +1-410-338-4340
    3700 San Martin Drive Fax: +1-410-338-4424
    Baltimore, MD 21218 U.S.A. http://www.stsci.edu/~postman



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